Uncaught Exception immediately after unlocking device

Recent change - upgraded OS from 4.2.something to 4.5 using the tools on the RIM website.

PROBLEM: after I enter my password to unlock the device, the main screen appears and is then overlaid with a message box. The message box text is "Uncaught exception - layout requested during layout". There is an OK button in the box, but none of the controls are active so I can't select it.

Basically this means the device is useless as anything other than a basic phone until the problem is resolved. I would appreciate any help. As an immediate solution I am going to see if I can still back down to the previous OS level, and if not the try re-installing this one.

Re: Uncaught Exception immediately after unlocking device

Thank you for that advice. I had tried removnig the battery before, but only after carefully turning the device off first.

CURRENT SITUATION: the same error box is there, with the same message. However, I can now ckick the OK button and it goes away. So now it is merely an aggravation instead of making the 8800 inoperable. Any additional suggestions will be appreciated.